Silane bonding agents have been used to treat silica fillers in a wide variety of resin systems to improve the adhesion of the resin matrix to the filler. In some cases, the bonding agent becomes part of the matrix. Typically, the bonding agent is an extension of a linear portion of the matrix chain, or a chain end. Such agents do not provide for cross-linking of the resin matrix.
U.S. Pat. Nos. 3,929,718 and 4,780,108 disclose treating silica particles with organosilicon compounds in order to increase the particles's density. The densified particles are used as fillers.
U.S. Pat. No. 2,938,009 describes filled organopolysiloxane compositions comprising a curable organopolysiloxane and filler particles coated with certain cyclic alkyl polysiloxanes.
U.S. Pat. No. 3,649,588 discloses treatment of fillers with low molecular weight organopolysiloxanes in the presence of an amino compound in order to render the filler hydrophobic and non-structure inducing. Hydrophobic filler mixtures for room temperature vulcanizable and low temperature vulcanizable silicone rubbers are disclosed in U.S. Pat. No. 4,307,023. The hydrophobizing agent is an organosilicone compound consisting of linear or cyclic organopolysiloxanes. Treatment of silica fillers with organosilicon compounds in order to render the filler hydrophobic is also taught in U.S. Pat. No. 5,057,151.
U.S. Pat. No. 3,654,215 discloses filler cross-linked polysiloxanes. This is accomplished by reacting a polysiloxane containing silanic hydrogen with a filler containing silanol groups in the presence of a platinum-containing catalyst. Cyclic dimethylsiloxanes and cyclic organosiloxanes containing silanic hydrogen are rearranged with alkaline or acid catalyst to give the desired curable organopolysiloxane.
U.S. Pat. No. 3,021,297 describes resins formed from chloromethylheptamethylcyclotetrasiloxane. The polymerized product, either with or without a filler, can be used for caulking.
Chloroheptamethylcyclotetrasiloxane was first prepared via chlorination of heptamethylcyclotetrasiloxane in CCl.sub.4 in high yield (Sokolov et al., J. Gen. Chem, U.S.S.R. 26, 1061-1063 (1956), incorporated herein by reference). The synthesis proceeds in very high yield with few side reactions. The subsequent use of this reagent has not been reported.